/* package whatever; // don't place package name! */
 
import java.util.*;
import java.lang.*;
import java.io.*;
 
/* Name of the class has to be "Main" only if the class is public. */
class Ideone
{
	public static void main (String[] args) throws java.lang.Exception
	{
	Scanner sc = new Scanner(System.in);
 
	float radio = sc.nextFloat();
 
	double resultado = 3.14159 * (radio*radio);
 
	System.out.print(resultado+"");
	System.out.println("");
	}
}

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Mi4wMA==

2.00